Fingershaking
The word “clueless” comes to mind. Truly.
It’s understood you do not quite comprehend a brain filled with daily, explicit, intruding visions of self-destruction. Why should you? Alike persons do not alike minds make.
However, it would be lovely if you considered that ideation and intent are not one and same. Ponder that ideation may, in fact, distress and disturb more than even the root causes. Understand you are privy for your own context and reference, not for shock value, answers or sympathy.
Would you rather a lie, a sin of omission? Little black mold hidden under scratch-and-sniff flower stickers? Something “lucid”?
Walk a mile. Try to understand. Listen silently. Be a friend. He does this well; learn by example.
Don’t shake your finger like that again… you’ve already acknowledged the line is a thin one, now worn even thinner.

